It is known to provide a vehicle diagnostics apparatus that connects to a diagnostics input port of a motor vehicle to facilitate interrogation of a vehicle electronic control unit (ECU). Known diagnostics apparatus is configured to read fault codes that are stored in a memory of the ECU when the ECU determines that a fault has occurred. The diagnostics apparatus typically provides an output to an operator indicative of the fault codes identified by the apparatus.
Known diagnostics apparatus may be operable to command an ECU to which it is connected via the diagnostics port to perform a particular diagnostic test and to read back from the ECU a result of the test.
A problem with known diagnostics apparatus is that it is only able to facilitate diagnosis of a fault by reference to an output provided by the diagnostics port alone. The apparatus may be unable to determine whether the output from the ECU provides a correct indication of the presence (or absence) of a fault. Furthermore, in the event a fault is determined to exist, the diagnostics apparatus may be unable to determine where the fault is located.
It is an aim of the present invention to address disadvantages associated with the prior art.